Computer networks are commonly used to send and receive data, to share resources, and to provide communication between remote and local users. In the Open Systems Interconnect (OSI) seven-layer reference model, a frame is a unit of data at the data link layer and a packet is a unit of data at the network level. Packets and frames may be referred to generally as data units.
Communication equipment such as network adaptors, routers, and switches are responsible for conveying data from one user to an intended other user using various communication protocols.
Switches, as they relate to computer networking and to Ethernet, are hardware-based devices which control the flow of data packets or cells based upon destination address information which is available in each packet. A properly designed and implemented switch should be capable of receiving a packet and switching the packet to an appropriate output port.
A stackable switch is a network switch that is fully functional operating standalone but which can also be set up by physical connectivity to operate together with one or more other network switches, with this group of switches showing the characteristics of a single switch but having the port capacity of the sum of the combined switches. Such a group created by physical interconnectivity is a physical network stack. Switches in a physical network stack are called member switches. The member switch that manages the physical network stack is the master switch.
A packet-switched network is a digital communications network that groups all transmitted data, irrespective of content, type, or structure into variable-length packets. The network over which packets are transmitted is a shared network which routes each packet independently from all others and allocates transmission resources as needed. A cell-based network is a digital communications network that uses fixed-length packets, called cells.